Build-up of atmospheric carbon dioxide is expected to have a detrimental impact on global weather conditions. Accordingly, there is a need for additional systems and/or methods that assist in mitigating the build-up of atmospheric carbon dioxide, including the sequestering of industrial CO2 emissions. Additionally, there is a need for a natural soil fertilizer that mitigates desertification and revitalizes the soil micronutrients depleted by chemical farming.
Soil microorganisms within BSC form a symbiotic group; a mutually beneficial relationship exists among components within the group, and with the plants in the associated healthy soil. Many of the microorganisms in BSC are photosynthetic and draw their energy from sunlight such that they can, in turn, manufacture and provide nutrition and fixed nitrogen to cohort microorganisms that are not photosynthetic or are found deeper in the soil. The actions of the BSC, and the deeper cohort microorganisms it supplies nutrition to, work together as a symbiotic group to stabilize soil and draw plant available nutrition from the grains of soil into the soil matrix over time. In addition, the dominant cyanobacteria component of BSC fixes carbon as well as nitrogen from the atmosphere. Beginning with BSC, the combined actions of these microorganisms create conditions benefiting the establishment and growth of vascular plants like grasses, shrubs and crops. In effect, the BSC is a naturally occurring solar powered fertilizer that lives on the surface of bare earth making it suitable and beneficial for the establishment of vascular plants over time.
However, because BSC microorganisms reproduce slowly in dry climates and are not very motile, physical disturbances like tilling, livestock grazing, and fire can halt the BSCs beneficial effects for the soil and the BSC, and these benefits can take decades or centuries in dry climates to naturally restore. Of the planet's 13 billion hectares of land mass, about 1 billion hectares of BSC supported soil have been damaged by human activity that has led to increased global desertification and airborne dust that exacerbates the effects of global warming. Once BSC activity declines, the vascular plants dependent on healthy soil decline, further reducing the ability of the land to produce crops, prevent erosion, and draw down CO2 from the atmosphere. Additionally, the use of factory fertilizers based on the energy-intensive Haber-Bosch process for fixing agricultural nitrogen increase levels of atmospheric CO2, pollute waterways with excess nitrogen run off, and deplete soil health and micronutrients.
The following prior art illustrates the progress made so far in the culturing and dissemination of cyanobacterial algae for the purpose of inoculating dry or damaged land with a living fertilizer in order to rejuvenate the biological soil crust, enable the growth of vascular plants, and sequester atmopheric CO2.
The use of cyanobacterial (blue-green) algae as a fertilizer has been proposed by U.S. Pat. Nos. 4,879,232 and 4,950,601, both to MacDonald et al., and by U.S. Pat. No. 4,921,803 to Nohr.
In U.S. Patent Application Publication No. 2008/0236227 to Flynn (herein after referred to as “Flynn”), a biological culture of natural soil microorganisms is drawn from their normal residence in the top centimeter of healthy undisturbed soil found in un-shaded areas. These blue-green algae and their soil consortia can be cultured into an inoculant in a manner taught by Flynn and used to inoculate a photobioreactor (or PBR) where the culture is grown in liquid media with ready access to nutrients, carbon dioxide, and light. Once the culture has increased in mass sufficiently, the inoculant is harvested and dehydrated for storage and later dissemination across arid land. Additives may be added such as fungi, other bacteria, mineral salts, and xeri-protectants. Flynn reports that certain methods of particle reduction, such as grinding, can cause cell damage that results in a lower rate of recovery for the dried inoculant, once exposed to sun and water. Pelletizing the inoculant via extrusion enhances survivability, but may not be the ideal aerodynamic size and shape for wide- spread dissemination, such as by aircraft crop dusting.
U.S. Pat. No. 4,774,186 to Schaefer Jr. et al. (herein after referred to as “Schaefer”) discloses an aqueous suspension comprising water, algae, and a carrier which is applied to the soil using a conventional irrigation system. The carrier comprises water dispersible particles, such as clay, lactose and other additives. The carrier is mixed with algae that is in a resting stage (essentially dry, dormant, and revivable) to produce a dry, flowable mixture which is then added to water near the site of application. Because the carrier will eventually be dissolved in water prior to application, it may not have the homogeneity that a compounded mixture destined for dry dissemination would need.
Youngs, in U.S. Patent Application Publication No. 2010/0224574 (herein after referred to as “Youngs”), teaches a method of water extraction from a culture of algae or other mixture. Herein, a culture of inoculant from a PBR is fed into a filter system that uses a capillary belt to efficiently remove the water from a desired soil inoculant, leaving a thin mat of moist algae that is substantially dry. Further dryers or air drying is employed to reduce the moist mat of algae to a dried and live flake that can be stored for later dissemination upon in arid land. Youngs, which is incorporated herein by reference, enables a large scale drying of algae and soil microorganisms to produce a viable algae particle.
The use of conventional PBR methods of culturing soil microorganisms in closed tanks results in a slow growth rate due to, among other reasons, sunlight penetrating the growth media by only centimeters, this growth rate being insufficient for large scale is production. U.S. Pat. No. 6,228,136 B1 issued to Riley et al (herein after referred to as “Riley”) teaches a method of growing thin-film cyanobacterial soil inoculant on a substrate made of hemp/cotton cloth and other materials. In Riley, the substrate provides for a faster growth rate since sunlight can easily penetrate a thin layer of growth media. The harvested substrate/algae is then dried and either laid onto the soil or chopped up and disseminated. Low temperature drying preserves the viability of the dried inoculant. Spools of substrate/algae can be wound up for more compact storage. The substrate pieces or sheets represent additional bulk and need to eventually disintegrate into the soil.
Underground injection of CO2 as a method of sequestering CO2 is proposed by Lackner in “A Guide To CO2 Sequestration”, SCIENCE Magazine, Vol. 300 Jun. 13, 2003. This CO2 is best provided by concentrated sources, such as industrial plants emitting CO2.
CO2 uptake by a growing culture of inoculant will vary by around a factor of 2 or more through a 24 hour cycle as the sunlight varies. The availability of higher concentrations of CO2 than are available from the atmosphere may enhance the growth rates of a culture, were they available. Also, emissions from an industrial source of CO2, such as a coal burning power plant, vary substantially across a day or days. There is currently no known coupling of an industrial source to a PBR culturing system that accounts for variations in industrial output.
Several shortcomings exist within the existing art that prevent large scale production, storage, and dissemination of a BSC inoculant. Rot and short shelf life of dried inoculant are key impediments; it is crucial that the inoculant is gently and thoroughly dried and preserved. Different soil types and dissemination methods require a different consortia of soil microorganisms having incompatible growth conditions, different optimum preservatives and nutrients, and different particle shape and size. For instance, aircraft crop dusting would likely require a different inoculant composition than land-based spreading or delivery through an irrigation system. What's needed is a flexible culturing and compounding system that can adapt the manufacturing process to maximally grow and preserve a symbiotic consortium of inoculant particles for a wide variety of target soil and dissemination methods on a large scale. Excess bulk, such as that created by a substrate method, should be avoided to eliminate the problem of decomposing substrate material and the additional bulk that would burden production, storage, and dissemination processes. There is therefore a need for a high capacity substrateless system of production. Also, the financial and technical challenges of any new technology requires leveraging any and all available synergies and options.